Catalytic cracking process

Abstract

A catalytic process for cracking vanadium-containing oils employs a physical mixture of (a) zeolite embedded in an inorganic matrix material and (b) magnesium oxide on alumina support.

That which is claimed is: 
     
       1. A catalytic cracking process comprising the step of contacting in a cracking zone a hydrocarbon containing feed stream having an initial boiling point of at least about 400° F., measured at about 0 psig, and containing vanadium impurities with a catalyst composition comprising a physical mixture of (a) zeolite embedded in an inorganic refractory matrix material, and   (b) magnesium oxide on alumina support material, under such cracking conditions as to obtain at least one liquid hydrocarbon containing product stream having a lower initial boiling point and a higher API gravity than said feed stream.     
     
     
       2. A process in accordance with claim 1 wherein said alumina support material consists essentially of alumina. 
     
     
       3. A process in accordance with claim 1 wherein said zeolite is selected from the group consisting of faujasite, chabazite, mordenite, offretite, erionite, Zeolon, zeolite X, zeolite Y, zeolite L, zeolite ZSM-4, zeolite ZSM-5, zeolite ZSM-11, zeolite ZSM-12, zeolite ZSM-23, zeolite ZSM-35, zeolite ZSM-38, zeolite ZSM-48 and mixtures thereof; and said inorganic refractory matrix material is selected from the group consisting of silica, alumina, silica-alumina, aluminosilicates, aluminum phosphate and mixtures thereof. 
     
     
       4. A process in accordance with claim 1 wherein the weight ratio of said zeolite to said inorganic refractory matrix material is in the range of from about 1:30 to about 1:1, and the BET/N 2  surface area of component (a) of said catalyst composition is in the range of from about 50 to about 800 m 2  /g. 
     
     
       5. A process in accordance with claim 1 wherein in component (b) of said catalyst composition the weight ratio of magnesia to alumina is in the range of from about 0.01:1 to about 2:1. 
     
     
       6. A process in accordance with claim 1 wherein the surface area of said component (b) of said catalyst composition has a surface area in the range of from about 100 to about 500 m 2  /g, and the weight ratio of magnesia to alumina is in the range of from about 0.05:1 to about 0.5:1. 
     
     
       7. A process in accordance with claim 1 wherein said component (b) of said catalyst composition has been prepared by a process comprising the steps of impregnating alumina with a suitable magnesium compound dissolved in a suitable liquid, drying the thus impregnated alumina, and calcining the dried, impregnated alumina under such conditions as to substantially convert said magnesium compound to MgO. 
     
     
       8. A process in accordance with claim 1 wherein in said catalyst composition the weight ratio of component (a) to component (b) is in the range of from about 1:2 to about 20:1. 
     
     
       9. A process in accordance with claim 1 wherein said weight ratio of component (a) to component (b) is in the range of from about 2:1 to about 8:1. 
     
     
       10. A process in accordance with claim 1 wherein said cracking catalyst composition additionally comprises about 0.1 to about 2.0 weight-% V as vanadium oxide. 
     
     
       11. A process in accordance with claim 1 wherein said feed stream contains about 1-200 ppmw V. 
     
     
       12. A process in accordance with claim 1 wherein said feed stream contains about 5-50 ppmw V and has a boiling range of from about 400° to about 1300° F., measured about 0 psig. 
     
     
       13. A process in accordance with claim 12, wherein said feed stream has an API gravity in the range of from about 5 to about 40, and contains about 0.1-20 weight-% Ramsbottom carbon residue and about 0.1-5 weight-% sulfur. 
     
     
       14. A process in accordance with claim 1 wherein said contacting is carried out in a fluidized-bed catalytic cracking reactor. 
     
     
       15. A process in accordance with claim 1 wherein said cracking conditions comprises a weight ratio of said catalyst composition to said hydrocarbon containing feed stream in the range of from about 2:1 to about 10:1, and a cracking temperature in the range of from about 800° to about 1200° F. 
     
     
       16. A process in accordance with claim 1 wherein steam is present during said contacting under cracking conditions and the weight ratio of steam to said hydrocarbon containing feed stream is in the range of from about 0.01:1 to about 0.5:1. 
     
     
       17. A process in accordance with claim 1 comprising the additional steps of removing said cracking catalyst composition from said cracking zone after it has been used in said cracking zone;   separating the thus removed cracking catalyst composition from gases and said at least one liquid product stream,   exposing at least a portion of the thus separated cracking catalyst composition to flowing steam so as to strip adhered liquids from said cracking catalyst composition, and   heating the thus steam-stripped cracking catalyst composition with a free oxygen containing gas so as to substantially remove coke deposits from said steam-stripped cracking catalyst composition, substantially convert vanadium compounds deposited thereon to vanadium oxide, and thus obtain a regenerated cracking catalyst composition.   
     
     
       18. A process in accordance with claim 17 further comprising the additional step of recycling at least a portion of said regenerated cracking catalyst composition to said cracking zone.   
     
     
       19. A process in accordance with claim 18, wherein fresh, unused cracking catalyst composition has been added to said regenerated catalyst composition before said recycling.